1. Field
One or more embodiments described herein relate to a battery.
2. Description of the Related Art
Unlike a primary battery, a rechargeable battery can be repeatedly charged and discharged. Low-capacity rechargeable batteries output low levels of power, and therefore are used in small portable electronic devices such as mobile phones, laptop computers, and camcorders. High-capacity rechargeable batteries are formed by coupling multiple rechargeable batteries in series to output high levels of power. These batteries are suitable for use in driving motors of electric vehicles. Also, rechargeable batteries may be formed to have a cylindrical or prismatic shape.
In order for a rechargeable battery to properly operate, a sufficient amount of electrolyte solution may be injected into the battery case for purposes of impregnating an electrode assembly therein. These batteries have also been equipped with a gasket and lower insulating member. The gasket is provided between a terminal and cap plate to prevent the electrolyte solution from contacting a terminal of the rechargeable battery. The lower insulating member is provided between the cap plate and a current collector.
When charging and discharging is continuously repeated, operating performance of the gasket and/or lower insulating member may deteriorate over time as a result of an increase in internal battery temperature or pressure. This deterioration may allow the electrolyte solution in the case to permeate between the gasket and one or more battery terminals, or between the lower insulating member and battery terminals. As a result, the terminals may erode by the electrolyte solution and short circuit may occur inside the battery. Also, a current path may form between the terminal and cap plate.
The gasket is to be compressed between the terminal and cap plate. Accordingly, the gasket has been made of a material having elasticity and rigidity. The lower insulating member is made of a material with less elasticity and less rigidity. These differences in materials may increase the cost of implementing the gasket and lower insulating member in the battery.
Attempts have been made to overcome these drawbacks. For example, the gasket and lower insulating member may be integrally formed to prevent terminal erosion or internal short-circuits caused by the electrolyte solution. This will allow the lower insulating material and gasket to be made of the same material. However, integrally forming the gasket and lower insulating also increases manufacturing costs because of the special design required for the integral formation.